CHICAGO — The number of measles cases in the U.S. has reached its highest point in 33 years, and outbreaks are expected to continue, especially amid national and international travel, says Northwestern University pediatric infectious disease expert Dr. Tina Tan.

“The continued increase in measles cases is evidence that the disease is very transmissible in unvaccinated populations,” said Tan, professor of pediatric infectious diseases at Northwestern University Feinberg School of Medicine and an infectious disease physician at Ann & Robert H. Lurie Children’s Hospital of Chicago. “Given this is summer and more people are traveling all over the U.S. and abroad, this will increase the spread of measles.

“People need to ensure that they, their children and their families are all up to date on their measles and other vaccines as this is the best way to protect and prevent persons from getting sick with measles and other vaccine-preventable diseases.”